140 likes | 146 Views
Briefing Materials. LTCP and TN Cost Allocation. Presented to:. Blue Plains Technical Experts Working Group. By: District of Columbia Water and Sewer Authority December 12, 2008. Purpose. Prepare for Jan 7, 2009 CAO meeting
E N D
Briefing Materials LTCP and TN Cost Allocation Presented to: Blue Plains Technical Experts Working Group By: District of Columbia Water and Sewer Authority December 12, 2008
Purpose • Prepare for Jan 7, 2009 CAO meeting • Present range of potential DC/suburban cost allocations for LTCP and TN based on WASA technical analyses
LTCP Differentiate between D.C.-only vs joint use projects Estimate suburban cost based on range of 6 to 12.7 % per Nov. 20, 2008 CAO meeting TN Estimate suburban cost based on 370 mgd IMA allocation Bases for Cost Allocations • Mixed LTCP & TN • Identify use (volume, flow rate, etc.) for LTCP vs TN • For LTCP: estimate suburban cost based on range of 6 to 12.7 % • For TN, estimate suburban cost based on 370 mgd allocation
Mixed LTCP & TN - Facilities Northeast Boundary Tunnel = LTCP = Mixed LTCP & TN Anacostia River Tunnel = Pure TN ECF 225 mgd Blue Plains Tunnel 73 mg total Tunnel Dewatering Pumping Station @ BP Enhanced Clarification 31 mg for TN • - 170 mgd planned for LTCP • 225 mgd needed overall • 55 mgd for TN Required only for TN (Replaces 336 mgd excess flow facilities)
Enhanced Clarification Facility • Not required for CSO control – can meet WQS under LTCP without it • Needed for TN • Required for peak flow reduction so overall pollutant loads to river are less with peaking factor of 1.5 vs 2.0 for peak plant flows • Key basis for EPA accepting plan
Overview of Costs and Categories LTCP – DC Only $410.5 M LTCP – DC + Subs $1,322.1 M DC Only CSO Program $2,360.5 Other Projects $364.5 M DC + Subs CSO & TN $3,219.2 M Mixed LTCP & TN – DC + Subs $436.0 M TN Program $858.7 Pure TN – DC + Subs $686.1 M
CSO Program – Other Projects • Examples: • Pumping station rehabilitations • Siphon cleaning • Blue Plains influent sewer rehabilitations • Procedures already established for determining: • Joint use vs non-joint use • Cost allocation
Mixed LTCP & TN - Facilities Calculation of Percentages: Calculation of Cost: 11
Evaluate TN Savings for Current Plan vs. No Change in Peaking Factor ($1.4 Billion Plan)
Summary Note: 1. CSO Program costs not directly tied to LTCP are budgeted at $364.5 M. These costs are not included since they will be allocated using procedures already established.